Bring my PC back to life! Power issues?

[Justin]

I'm trying to resuscitate an old PC of mine. Every time I switch on it starts to boot and then goes off. When I subseqently switch on it stays on for 2 seconds and then powers off again.

I thought it was a PSU problem and have connected to another unit but problem still occurs. Checked the front panel power button and appears to be connected ok, nothing loose.

Pulling my hair out now, removed memory but makes no difference.

Anyone any ideas?

[Paul]

how far it goes when booting?

[Kaz]

Have you re-seated the CPU?

[Justin]

Trying it now, it starts up for just a second and then powers off. Keeping the button held in it starts/stops over and over. I'll check the CPU now. I did re-seat the heatsink after applying new paste.

[Kaz]

You've maybe put too much paste on the heatsink, which means the CPU will overheat as the paste acts as a barrier, hence why it's shutting itself down again

[Justin]

Just re-seated cpu. I only put a small amount of paste on, always the size of a grain of rice and ensure it's spread evenly. I don't think it's a heating issue as it's powering off almost immediately. Every now and then it gets to the boot stage and then powers off.

[Kaz]

Try stripping everything out of the case and build it on a table, short out the power pins to get it to boot and see how you get on from there.

It's easier to fault find when it's on a table instead of in a case

[Justin]

I've been after a test chassis for a while but not easy to come by, never in stock. Might build something myself.

http://www.kustompcs.co.uk/acatalog/Kus ... s_105.html

[Justin]

OK, might be getting somewhere. I removed the Graphics Card and rebooted. Obv. the PC halts with an error beep because it can't find the card but power stays on. Numerous reboots and power stays on. Tried a graphics card from my working PC and same error happens, boots/powers off immediately and so on.

I'm assuming from this that the AGP graphics slot may be faulty. Maybe the mobo has started to pack up on me.

[Kaz]

Could be a faulty slot, but more than likely it's that the PSU isn't big enough to run everything